ClamAV and out of memory

I have VPS with 384MB of RAM and running Debian Lenny on it. I followed perfect server howto for ISPConfig 3.0.3 and ended up on following error. Everything else looks like working just fine but I can't sent or receive any email. I did find this error on ClamAV start:

Thanks for the link. So my VPS provider has next RAM option 512MB so what you think should that be enough to run also clamav? This server will have less that ten email accounts and only few domains and websites with quite low traffic. Maybe about 10-20GB/year.